/*
    File: RecentCommandsController.m
Abstract: 
A table view controller to manage and display a list of recent search strings.
The search strings are stored in NSUserDefaults to maintain the list between launches of the application.
The view controller manages two arrays:
* recentSearches is the array that corresponds to the full set of recent search strings stored in user defaults.
* displayedRecentSearches is an array derived from recent searches, filtered by the current search string (if any).

The recentSearches array is kept synchronized with user defaults, and avoids the need to query user defaults every time the search string is updated.

The table view displays the contents of the displayedRecentSearches array.

The view controller has a delegate that it notifies if row in the table view is selected.
	
 Version: 1.0

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*/

#import "GCConfig.h"
#import "ARDetectionViewController.h"
#import "RecentCommandsController.h"


NSString *RecentSearchesKey = @"RecentSearchesKey";


@implementation RecentCommandsController

@synthesize delegate, recentSearches, displayedRecentSearches, clearButtonItem;


#pragma mark -
#pragma mark View lifecycle

- (void)viewDidLoad {
    [super viewDidLoad];

    self.title = @"Commands";
    self.contentSizeForViewInPopover = CGSizeMake(400.0, 280.0);
	self.tableView.backgroundColor = [UIColor lightGrayColor];

    // Set up the recent searches list, from user defaults or using an empty array.
    NSArray *recents = [[NSUserDefaults standardUserDefaults] 
						objectForKey:RecentSearchesKey];
    if (recents && recents.count) {
        self.recentSearches = recents;
        self.displayedRecentSearches = recents;
    }
    else {
        self.recentSearches = [NSArray array];
        self.displayedRecentSearches = [NSArray array];
    }
	
    // Create a button item to clear the recents list.
    UIBarButtonItem *aButtonItem = [[UIBarButtonItem alloc] 
									initWithTitle:@"Clear" 
									style:UIBarButtonItemStyleBordered 
									target:self 
									action:@selector(showClearRecentsAlert:)];
    self.clearButtonItem = aButtonItem;
    [aButtonItem release];
    
    if ([recentSearches count] == 0) {
        // Disable the button if there are no recents items.
        clearButtonItem.enabled = NO;
    }    
    self.navigationItem.leftBarButtonItem = clearButtonItem;
	
	NSArray *knownCommands = [[GCConfig sharedConfig].commands allKeys];
	for (NSString *aCommand in knownCommands) {
		[self addToRecentSearches: aCommand];		
	}
}


- (void)viewWillAppear:(BOOL)animated {
 
    // Ensure the complete list of recents is shown on first display.
    [super viewWillAppear:animated];
	
    self.displayedRecentSearches = recentSearches;
}


- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    return NO;
}


- (void)viewDidUnload {
    [super viewDidUnload];
    self.recentSearches = nil;
    self.displayedRecentSearches = nil;
}


#pragma mark -
#pragma mark Managing the recents list

- (void)addToRecentSearches:(NSString *)searchString {
    
    // Filter out any strings that shouldn't be in the recents list.
    if ([searchString isEqualToString:@""]) {
        return;
    }
    
    // Create a mutable copy of recent searches and remove the search string if it's already there (it's added to the top of the list later).

    NSMutableArray *mutableRecents = [recentSearches mutableCopy];
    [mutableRecents removeObject:searchString];
    
    // Add the new string at the top of the list.
    [mutableRecents insertObject:searchString atIndex:0];
    
    // Update user defaults.
	if (mutableRecents && mutableRecents.count) {
		[[NSUserDefaults standardUserDefaults] setObject:mutableRecents 
												  forKey:RecentSearchesKey];
	}

    // Set self's recent searches to the new recents array, and reload the table view.
    self.recentSearches = mutableRecents;
    self.displayedRecentSearches = mutableRecents;
    [self.tableView reloadData];
        
    // Ensure the clear button is enabled.
    clearButtonItem.enabled = YES;
}


- (void)filterResultsUsingString:(NSString *)filterString {

    /*
		If the search string is zero-length, then restore the recent searches, 
		otherwise create a predicate to filter the recent searches using the search string.
     */
    if ([filterString length] == 0) {
        self.displayedRecentSearches = recentSearches;
    }
    else {
        NSPredicate *filterPredicate = [NSPredicate predicateWithFormat:@"self BEGINSWITH[cd] %@", filterString];
        NSArray *filteredRecentSearches = [recentSearches 
										   filteredArrayUsingPredicate:filterPredicate];
        self.displayedRecentSearches = filteredRecentSearches;
    }

    [self.tableView reloadData];
}


- (void)showClearRecentsAlert:(id)sender {
    
    // If the user taps the Clear Recents button, present an action sheet to confirm.
    UIActionSheet *actionSheet = [[UIActionSheet alloc] 
								  initWithTitle:@"" 
								  delegate:self 
								  cancelButtonTitle:@"Cancel" 
								  destructiveButtonTitle:@"Clear All Recents" 
								  otherButtonTitles:nil];
    [actionSheet showInView:self.view];
    [actionSheet release];
}


- (void)actionSheet:(UIActionSheet *)actionSheet 
clickedButtonAtIndex:(NSInteger)buttonIndex {
    
    if (buttonIndex == 0) {
        /*
         If the user chose to clear recents, remove the recents entry from user defaults, set the list to an empty array, and redisplay the table view.
         */
        [[NSUserDefaults standardUserDefaults] setObject:nil forKey:RecentSearchesKey];
        self.recentSearches = [NSArray array];
        self.displayedRecentSearches = [NSArray array];
        [self.tableView reloadData];
        clearButtonItem.enabled = NO;
    }
}


#pragma mark Table view methods

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return [displayedRecentSearches count];
}


// Display the strings in displayedRecentSearches.
- (UITableViewCell *)tableView:(UITableView *)tableView 
		 cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    
    static NSString *CellIdentifier = @"Cell";
    
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[[UITableViewCell alloc] 
				 initWithStyle:UITableViewCellStyleDefault 
				 reuseIdentifier:CellIdentifier] 
				autorelease];
    }
    
    cell.textLabel.text = [displayedRecentSearches objectAtIndex:indexPath.row];    
    return cell;
}


- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    // Notify the delegate if a row is selected.
    [delegate recentCommandsController:self didSelectString:[displayedRecentSearches objectAtIndex:indexPath.row]];
}


#pragma mark -
#pragma mark Memory management

- (void)dealloc {
    [recentSearches release];
    [displayedRecentSearches release];
    [clearButtonItem release];
    [super dealloc];
}


@end

